probe: Add test for syncing a delete when the remote 404s
probe: Add test for syncing a delete when the remote 404s

This works fine; we continue processing the other rows in the DB. But it
*does* take longer than it really ought to require. See the related bug;
we ought to be able to shave some 17s off the test time by not retrying
on the 404.

Change-Id: I9ca2511651e9b2bc0045894baa4062d20bc15369
Related-Bug: #1849841

openstack/swift,tipabu/swift,swiftstack/swift,tipabu/swift,swiftstack/swift,tipabu/swift,openstack/swift,swiftstack/swift,openstack/swift,openstack/swift,tipabu/swift